Mercury MerCruiser Quicksilver Ignition Coil 8M0054588
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Mercury MerCruiser Ignition Coil – MPI ECM 555 Applications
Part Number: 8M0054588 (392-8M0054588)
Brand: Mercury / Quicksilver
GTIN: 745061877849
Compatible Applications
- MerCruiser 4.3L MPI (ECM 555) – 2001 and newer, serial 0M300000–2A455878
- MerCruiser 5.0L MPI (ECM 555) – 2001 and newer, serial 0M300000–2A455878
- MerCruiser 5.7L / 350 MAG MPI (ECM 555) – 2001 and newer, serial 0M300000–2A455878
- MerCruiser 6.2L / MX 6.2L MPI (ECM 555) – 2001 and newer, serial 0M300000–2A455878
- Sterndrive and inboard (MIE) configurations with ECM 555 ignition
Fitment Note: Confirm your engine serial number and ignition system configuration before ordering. This coil is specific to ECM 555 MPI applications within serial range 0M300000–2A455878. Similar MerCruiser engines using Thunderbolt or other ignition systems require different coils.
Superseded Part Numbers
- 863704
- 863704T
When to Replace
- Weak or absent spark confirmed by diagnostic testing
- Intermittent ignition failure or engine misfire
- Internal coil failure
- Physical damage to the coil housing or terminals
Properly diagnose misfire symptoms before replacing the coil.
Installation Notes
- Disconnect battery power before beginning any ignition system service
- Inspect the coil bracket, primary wiring, high-tension lead, distributor cap, rotor, and connectors before installing
- Reconnect all terminals securely
- Verify correct ignition operation after replacement
Parts Desk Insights
The critical identifiers for this coil are MPI + ECM 555 + serial range 0M300000–2A455878. Matching the ignition system type matters more than engine displacement alone — MerCruiser produced similar 4.3L and V8 engines across multiple ignition platforms, and using the wrong coil is a common ordering mistake. When in doubt, confirm ECM 555 before ordering.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.